Outdoor Power Equipment and Small Engines - Lawnboy starts, runs, then dies

I have a circa 1996 Lawnboy silver series, 4.5 hp, 2-cycle lawnmower. OK, I realize that it's not the best machine in the world, but until now it has been reliable. I've had it serviced regularly. This year, it will start with one or two pulls, run for a while (appx. 20 - 30 minutes), then shut down. If I let it sit for about 30 minutes, it will start up again and run for a while longer. I had a similar problem with a lawnboy which I had until I replaced it with this one. My dealer says the problem its the electronic ingition module. He says that this is a common problem with lawnboys. Before I pay to have it done, or do it myself, does anyone have any suggestions?

The technician is likely on the mark with the module but before you touch this, give us the model & serial numbers on the frame of the mower and we can advise you better. After posting these numbers and until you hear back from us, check to see if the fuel cap is venting properly. When the problem occurs, immediately loosen the cap and try to restart. Let us know.

The model no. is 10301 and the serial no. is 5939042. I used it last night and when, predictably after 15 - 20 minutes, it began to stall I unscrewed the gas cap and was able to keep it going. I'll clean the vent hole and see if this resolves the problem. Also, the last time I had it in for service, the mechanic adjusted the motor speed to 3200 rpm max - any long term problems with this? Thanks - JMM

You may or may not be able to clear the venting depending on the type cap you have. If the cap vents through the threads, you likely lost component(s) to the cap and will need to replace it. (Be sure to look for the component(s) (two at most) in the fuel tank though if you're not sure if you lost it/them).